Method for fabricating a non-parallel magnetically biased multiple magnetoresistive (MR) layer magnetoresistive (MR) sensor element

ABSTRACT

Within a method for forming a magnetoresistive (MR) sensor element there is first provided a substrate. There is then formed over the substrate a first magnetoresistive (MR) layer having formed contacting the first magnetoresistive (MR) layer a magnetically biased first magnetic bias layer biased in a first magnetic bias direction with a first magnetic bias field strength. There is also formed separated from the first magnetoresistive (MR) layer by a spacer layer a second magnetoresistive (MR) layer having formed contacting the second magnetoresistive (MR) layer a magnetically un-biased second magnetic bias layer. There is then biased through use of a first thermal annealing method employing a first thermal annealing temperature, a first thermal annealing exposure time and a first extrinsic magnetic bias field the magnetically un-biased second magnetic bias layer to form a magnetically biased second magnetic bias layer having a second magnetic bias field strength in a second magnetic bias direction non-parallel to the first magnetic bias direction while simultaneously partially demagnetizing the magnetically biased first magnetic bias layer to provide a partially demagnetized magnetically biased first magnetic bias layer having a partially demagnetized first magnetic bias field strength less than the first magnetic bias field strength. Finally, there is then annealed thermally through use of a second thermal annealing employing a second thermal annealing temperature and a second thermal annealing exposure time without a second magnetic bias field: (1) the partially demagnetized magnetically biased first magnetic bias layer to form a remagnetized partially demagnetized first magnetic bias layer having a remagnetized partially demagnetized first netic bias field strength greater than the partially demagnetized first magnetic bias field strength; and (2) the magnetically biased second magnetic bias layer to form a further magnetically biased second magnetic bias layer having a further magnetized second magnetic bias field strength greater than the second magnetic bias field strength.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to co-assigned applications: (1) Ser. No.09/182,761, filed Oct. 30, 1998, titled “Canted Longitudinal PatternedExchange Biased Dual-Stripe Magnetoresistive (DSMR) Sensor Element andMethod for Fabrication Thereof”; and (2) Ser. No. 09/182,775, also filedOct. 30, 1998, titled “Anti-Parallel Longitudinal Patterned ExchangeBiased Dual Stripe Magnetoresistive (DSMR) Sensor Element and Method forFabrication Thereof”, the teachings and citations from both of whichrelated co-assigned applications are incorporated herein fully byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to methods for fabricatingmagnetic sensor elements. More particularly, the present inventionrelates to methods for fabricating non-parallel magnetically biasedmultiple magnetoresistive (MR) layer magnetoresistive (MR) sensorelements.

2. Description of the Related Art

The recent and continuing advances in computer and informationtechnology have been made possible not only by the correlating advancesin the functionality, reliability and speed of semiconductor integratedcircuits, but also by the correlating advances in the storage densityand reliability of direct access storage devices (DASDs) employed indigitally encoded magnetic data storage and retrieval.

Storage density of direct access storage devices (DASDs) is typicallydetermined as areal storage density of a magnetic data storage mediumformed upon a rotating magnetic data storage disk within a direct accessstorage device (DASD) magnetic data storage enclosure. The areal storagedensity of the magnetic data storage medium is defined largely by thetrack width, the track spacing and the linear magnetic domain densitywithin the magnetic data storage medium. The track width, the trackspacing and the linear magnetic domain density within the magnetic datastorage medium are in turn determined by several principal factors,including but not limited to: (1) the magnetic read-writecharacteristics of a magnetic read-write head employed in reading andwriting digitally encoded magnetic data from and into the magnetic datastorage medium; (2) the magnetic domain characteristics of the magneticdata storage medium; and (3) the separation distance of the magneticread-write head from the magnetic data storage medium.

With regard to the magnetic read-write characteristics of magneticread-write heads employed in reading and writing digitally encodedmagnetic data from and into a magnetic data storage medium, it is knownin the art of magnetic read-write head fabrication that magnetoresistive(MR) sensor elements employed within magnetoresistive (MR) read-writeheads are generally superior to other types of magnetic sensor elementswhen employed in retrieving digitally encoded magnetic data from amagnetic data storage medium. In that regard, magnetoresistive (MR)sensor elements are generally regarded as superior sincemagnetoresistive (MR) sensor elements are known in the art to providehigh output digital read signal amplitudes, with good linear resolution,independent of the relative velocity of a magnetic data storage mediumwith respect to a magnetoresistive (MR) read-write head having themagnetoresistive (MR) sensor element incorporated therein.

Within the general category of magnetoresistive (MR) sensor elements,magnetoresistive (MR) sensor elements which employ multiplemagnetoresistive (MR) layers (typically including a pair ofmagnetoresistive (MR) layers), such as but not limited to dual stripemagnetoresistive (DSMR) sensor elements and spin valve magnetoresistive(DSVM) sensor elements, and in particular magnetoresistive (MR) sensorelements which employ multiple magnetoresistive (MR) layers at least oneof which is magnetically biased to provide non-parallel magnetic biasdirections of the multiple magnetoresistive (MR) layer magnetoresistive(MR) sensor elements, such as nominally anti-parallel longitudinallymagnetically biased dual stripe magnetoresistive (DSMR) sensor elementsand nominally perpendicularly magnetically biased spin valvemagnetoresistive (DSVMR) sensor elements, are presently of considerableinterest insofar as the magnetically biased magnetoresistive (MR) layersemployed within such magnetically biased multiple magnetoresistive (MR)layer magnetoresistive (MR) sensor elements typically provide enhancedmagnetic read signal amplitude and fidelity in comparison with singlestripe magnetoresistive (MR) sensor elements, non-magnetically biasedmultiple magnetoresistive (MR) layer magnetoresistive (MR) sensorelements and parallel magnetically biased multiple magnetoresistive (MR)layer magnetoresistive (MR) sensor elements.

While non-parallel magnetically biased multiple magnetoresistive (MR)layer magnetoresistive (MR) sensor elements such as but not limited tonon-parallel longitudinally magnetically biased dual stripemagnetoresistive (DSMR) sensor elements and non-parallel perpendicularlymagnetically biased dual spin valve magnetoresistive (DSVMR) sensorelements are thus desirable within the art of digitally encoded magneticdata storage and retrieval, non-parallel multiple magnetoresistive (MR)layer magnetoresistive (MR) sensor elements are nonetheless notfabricated entirely without problems in the art of magnetoresistive (MR)sensor element fabrication. In particular, as a data track width withina magnetic medium employed within digitally encoded magnetic datastorage and retrieval decreases, it becomes increasingly important thata read track width within a non-parallel magnetically biased multiplemagnetoresistive (MR) layer magnetoresistive (MR) sensor elementemployed in reading the data within the data track be uniformlymagnetically biased (i.e. have a uniform cross-track magnetic biasprofile). Uniform cross-track magnetic bias profiles are desirablewithin read track widths of non-parallel magnetically biased multiplemagnetoresistive (MR) layer magnetoresistive (MR) sensor elements sincesuch uniform cross-track magnetic bias profiles provide for optimalmagnetic read signal amplitudes within such non-parallel magneticallybiased multiple magnetoresistive (MR) layer magnetoresistive (MR) sensorelements.

It is thus towards the goal of providing, for use within magnetic datastorage and retrieval, a method for forming a non-parallel magneticallybiased multiple magnetoresistive (MR) layer magnetoresistive (MR) sensorelement with a uniform cross-track magnetic bias profile across a readtrack width of the non-parallel magnetically biased multiplemagnetoresistive (MR) layer magnetoresistive (MR) sensor element, aswell as a non-parallel magnetically biased multiple magnetoresistive(MR) layer magnetoresistive (MR) sensor element formed in accord withthe method, that the present invention is most generally directed.

Various methods and resultant magnetoresistive (MR) sensor elementstructures have been disclosed in the art of magnetoresistive (MR)sensor element fabrication for forming magnetically biasedmagnetoresistive (MR) sensor elements with enhanced functionality,enhanced reliability or other desirable properties.

For example, Voegeli et al., in U.S. Pat. No. 5,561,896, discloses amethod for fabricating, with enhanced longitudinal magnetic biascharacteristics, enhanced fabrication simplicity and enhancedreliability, a longitudinally magnetically biased magnetoresistive (MR)sensor element for use within magnetic data storage and retrieval. Themethod employs an “H” shaped laminate formed of a soft magnetoresistive(MR) material layer laminated to an interdiffusion material layer, whereupon thermally induced interdiffusion of the soft magnetoresistive (MR)material layer and the interdiffusion material layer there is formed ahard magnetic bias material layer therefrom, and where interdiffusion ofthe soft magnetoresistive (MR) material layer with the interdiffusionmaterial layer is effected by an electrical pulsing through a pair ofleg portions of the “H” but not a horizontal connector portion of the“H”, such that the pair of leg portions of the “H” is transformed into apair of hard magnetic bias material layers while the horizontalconnector portion of the “H” remains un-interdiffused as the softmagnetoresistive (MR) material layer which is longitudinallymagnetically biased by the pair of hard bias magnetic bias materiallayers formed from the thermally interdiffused leg portions of the

In addition, Dovek et al., in U.S. Pat. No. 5,650,887, discloses asystem for retrieving magnetic data from a magnetic data storage mediumwhile employing a spin valve magnetoresistive (SVMR) sensor element, anda disk drive magnetic data storage enclosure which employs the systemfor retrieving the magnetic data from the magnetic data storage mediumwhile employing the spin valve magnetoresistive (SVMR) sensor element,where the spin-valve magnetoresistive (SVMR) sensor element may bereadily reset to its original magnetic orientation subsequent to anevent which dislocates within the spin valve magnetoresistive (SVMR)sensor element a magnetic exchange bias pinned layer from its originalmagnetic orientation within the spin-valve magnetoresistive (SVMR)sensor element. To achieve the foregoing result, the system employs: (1)an electrical current waveform directed through the spin-valvemagnetoresistive (SVMR) sensor element with an initial currentsufficient to heat a magnetic exchange bias pinning layer within thespin-valve magnetoresistive (SVMR) sensor element above its blockingtemperature; and (2) a subsequent lower current sufficient to generate amagnetic field around the magnetic exchange bias pinned layer pinned bythe magnetic exchange bias pinning layer to properly magnetically orientthe magnetic exchange bias pinned layer while the magnetic exchange biaspinning layer is cooling below its blocking temperature.

Further, Shi et al., in U.S. Pat. No. 5,684,658, discloses a dual stripemagnetoresistive (DSMR) sensor element and a method for fabricating thedual stripe magnetoresistive (DSMR) sensor element, where the dualstripe magnetoresistive (DSMR) sensor element has a narrow read backwidth which in turn provides that the narrow read back width dual stripemagnetoresistive (DSMR) sensor element may be employed for readingdigitally encoded magnetic data within narrowly spaced tracks within amagnetic data storage medium. The dual stripe magnetoresistive (DSMR)sensor element realizes the foregoing object by employing when formingthe dual stripe magnetoresistive (DSMR) sensor element: (1) an offset ofa first magnetoresistive (MR) layer with respect to a secondmagnetoresistive (MR) layer within the dual stripe magnetoresistive(DSMR) sensor element; (2) a parallel longitudinal magnetic biasing ofthe first magnetoresistive (MR) layer with respect to the secondmagnetoresistive (MR) layer within the dual stripe magnetoresistive(DSMR) sensor element; and (3) an anti-parallel electromagnetic biasingof the first magnetoresistive (MR) layer with respect to the secondmagnetoresistive (MR) layer within the dual stripe magnetoresistive(DSMR) sensor element.

Still further, Han et al., in U.S. Pat. No. 5,783,460, discloses amethod for fabricating a dual stripe magnetoresistive (DSMR) sensorelement, where there is minimized tolerance variations with respect tothe width and/or alignment between a pair of magnetoresistive (MR)layers within the dual stripe magnetoresistive (DSMR) sensor element. Torealize the foregoing object, the method employs a lift off stencil asan etch mask for forming from a trilayer blanket stack layer comprising:(1) a blanket first magnetoresistive (MR) layer having formed thereupon;(2) a blanket inter-stripe dielectric layer, in turn having formedthereupon; (3) a blanket second magnetoresistive (MR) layer, acorresponding trilayer patterned stack layer comprising: (1) patternedfirst magnetoresistive (MR) layer having formed thereupon; (2) apatterned inter-stripe dielectric layer in turn having formed thereupon;(3) a patterned second magnetoresistive (MR) layer, wherein the seriesof three foregoing patterned layers within the trilayer patterned stacklayer in turn has a series of fully aligned edges.

Finally, Ohtsuka et al., in U.S. Pat. No. 5,859,753, discloses aspin-valve magnetoresistive (SVMR) sensor element, and a method forfabricating the spin-valve magnetoresistive (SVMR) sensor element, wherethe spin-valve magnetoresistive (SVMR) sensor element has an attenuatedsusceptibility to thermal asperities and electrostatic discharge whenemploying the spin-valve magnetoresistive (SVMR ) sensor element forretrieving magnetic data from a magnetic data storage medium. Thespin-valve magnetoresistive (SVMR) sensor element realizes the foregoingobjects by employing a dual spin-valve magnetoresistive (DSVMR) sensorelement construction wherein: (1) a pair of pinned magnetoresistivelayers within the dual spin-valve magnetoresistive (DSVMR) sensorelement is magnetically pinned in opposite directions; and (2) oneconductor lead layer within each pair of conductor lead layers employedwithin the dual spin-valve magnetoresistive (DSVMR) sensor elementconstruction is positioned with respect to the magnetic data storagemedium from which is retrieved magnetic data further removed than theother conductor lead layer within the pair of conductor lead layers.

Desirable within the art of non-parallel magnetically biased multiplemagnetoresistive (MR) layer magnetoresistive (MR) sensor elementfabrication are additional methods and materials which may be employedfor forming non-parallel magnetically biased multiple magnetoresistive(MR) layer magnetoresistive (MR) sensor elements with enhanced magneticbias profile uniformity of the non-parallel magnetically biased multiplemagnetoresistive (MR) layer magnetoresistive (MR) sensor elements withinthe trackwidths of the non-parallel magnetically biased multiplemagnetoresistive (MR) layer magnetoresistive (MR) sensor elements.

It is towards the foregoing object that the present invention isdirected.

SUMMARY OF THE INVENTION

A first object of the present invention is to provide a non-parallelmagnetically biased multiple magnetoresistive (MR) layermagnetoresistive (MR) sensor element, and a method for fabricating thenon-parallel magnetically biased multiple magnetoresistive (MR) layermagnetoresistive (MR) sensor element, where the non-parallelmagnetically biased multiple magnetoresistive (MR) layermagnetoresistive (MR) sensor element has an enhanced magnetic biasprofile uniformity within a trackwidth of the non-parallel magneticallybiased multiple magnetoresistive (MR) layer magnetoresistive (MR) sensorelement.

A second object of the present invention is to provide a non-parallelmagnetically biased multiple magnetoresistive (MR) layermagnetoresistive (MR) sensor element and a method for fabricating thenon-parallel magnetically biased multiple magnetoresistive (MR) layermagnetoresistive (MR) sensor element in accord with the first object ofthe present invention, which method is readily commercially implemented.

In accord with the objects of the present invention, there is providedby the present invention a method for fabricating a non-parallelmagnetically biased multiple magnetoresistive (MR) layermagnetoresistive (MR) sensor element. To practice the method of thepresent invention, there is first provided a substrate. There is thenformed over the substrate a first magnetoresistive (MR) layer. There isalso formed contacting the first magnetoresistive (MR) layer amagnetically biased first magnetic bias layer, where the magneticallybiased first magnetic bias layer is biased in a first magnetic biasdirection with a first magnetic bias field strength. There is alsoformed separated from the first magnetoresistive (MR) layer by a spacerlayer a second magnetoresistive (MR) layer. There is also formedcontacting the second magnetoresistive (MR) layer a magneticallyun-biased second magnetic bias layer. There is then biased through useof a first thermal annealing method employing a first thermal annealingtemperature, a first thermal annealing exposure time and a firstextrinsic magnetic bias field strength the magnetically un-biased secondmagnetic bias layer to form a magnetically biased second magnetic biaslayer having a second magnetic bias field strength in a second magneticbias direction non-parallel to the first magnetic bias direction whilesimultaneously partially demagnetizing the magnetically biased firstmagnetic bias layer to form a partially demagnetized magnetically biasedfirst magnetic bias layer having a partially demagnetized first magneticbias field strength less than the first magnetic bias field strength.Finally, there is then annealed thermally through use of a secondthermal annealing employing a second thermal annealing temperature and asecond thermal annealing exposure time without a second magnetic biasfield: (1) the partially demagnetized magnetically biased first magneticbias layer to form a remagnetized partially demagnetized first magneticbias layer having a remagnetized partially demagnetized first magneticbias field strength greater than the partially demagnetized firstmagnetic bias field strength; and (2) the magnetically biased secondmagnetic bias layer to form a further magnetically biased secondmagnetic bias layer having a further magnetized second magnetic biasfield strength greater than the second magnetic bias field strength.

Advantageously, the method of the present invention provides that: (1) afirst magnetic bias layer from which is formed the magnetically biasedfirst magnetic bias layer; and (2) the second magnetic bias layer, mayboth be formed from a single magnetic bias material. Thus, use of such asingle magnetic bias material assists in optimizing a cross-trackmagnetic bias profile uniformity of a non-parallel magnetically biasedmultiple magnetoresistive (MR) layer magnetoresistive (MR) sensorelement. To the extent not previously disclosed or claimed within theart of magnetoresistive (MR) sensor element fabrication, the presentinvention also contemplates various non-parallel magnetically biasedmultiple magnetoresistive (MR) layer magnetoresistive (MR) sensorelements formed employing multiple non-parallel magnetically biasedmagnetic bias layers formed of a single magnetic bias material.

The present invention provides a non-parallel magnetically biasedmultiple magnetoresistive (MR) layer magnetoresistive (MR) sensorelement, and a method for fabricating the non-parallel magneticallybiased multiple magnetoresistive (MR) layer magnetoresistive (MR) sensorelement, where the non-parallel magnetically biased multiplemagnetoresistive (MR) layer magnetoresistive (MR) sensor element has anenhanced magnetic bias profile uniformity within a trackwidth of thenon-parallel magnetically biased multiple magnetoresistive (MR) layermagnetoresistive (MR) sensor element. The method of the presentinvention realizes the foregoing object by employing when fabricatingthe non-parallel magnetically biased multiple magnetoresistive (MR)layer magnetoresistive (MR) sensor element: (1) a first thermalannealing method employing a first thermal annealing temperature, afirst thermal annealing exposure time and a first extrinsic magneticbias field strength to form from a magnetically un-biased secondmagnetic bias layer a magnetically biased second magnetic bias layerhaving a second magnetic bias field strength in a second magnetic biasdirection non-parallel to a first magnetic bias direction of amagnetically biased first magnetic bias layer, while simultaneouslypartially demagnetizing the magnetically biased first magnetic biaslayer to provide a partially demagnetized magnetically biased firstmagnetic bias layer having a partially demagnetized first magnetic biasfield strength less than a first magnetic bias field strength; and (2) asecond thermal annealing method employing a second thermal annealingtemperature and a second thermal annealing exposure time without asecond magnetic bias field: (a) to form from the partially demagnetizedmagnetically biased first magnetic bias layer a remagnetized partiallydemagnetized first magnetic bias layer having a remagnetized partiallydemagnetized first magnetic bias field strength greater than thepartially demagnetized first magnetic bias field strength; and (b) toform from the magnetically biased second magnetic bias layer a furthermagnetically biased second magnetic bias layer having a furthermagnetized second magnetic bias field strength greater than the secondmagnetic bias field strength.

The method of the present invention is readily commercially implemented.The method of the present invention employs thermal annealing methodswhich are generally known in the art of magnetoresistive (MR) sensorelement fabrication. Since it is a process control within the presentinvention which provides at least in part the method of the presentinvention, rather than the existence of methods and materials whichprovides the present invention, the method of the present invention isreadily commercially implemented.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, features and advantages of the present invention areunderstood within the context of the Description of the PreferredEmbodiment, as set forth below. The Description of the PreferredEmbodiment is understood within the context of the accompanyingdrawings, which form a material part of this disclosure, wherein:

FIG. 1, FIG. 2, FIG. 3a, FIG. 3b, FIG. 4a, FIG. 4b, FIG. 5a, FIG. 5b andFIG. 6 show a series of schematic air bearing surface (ABS) viewdiagrams and schematic perspective view diagrams illustrating theresults of progressive stages in forming a merged inductive magneticwrite dual stripe magnetoresistive (DSMR) read magnetic read-write headhaving formed therein an anti-parallel magnetically biased dual stripemagnetoresistive (DSMR) sensor element in accord with a preferredembodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides a non-parallel magnetically biasedmultiple magnetoresistive (MR) layer magnetoresistive (MR) sensorelement, and a method for fabricating the non-parallel magneticallybiased multiple magnetoresistive (MR) layer magnetoresistive (MR) sensorelement, where the non-parallel magnetically biased multiplemagnetoresistive (MR) layer magnetoresistive (MR) sensor element has anenhanced magnetic bias profile uniformity within a trackwidth of thenon-parallel magnetically biased multiple magnetoresistive (MR) layermagnetoresistive (MR) sensor element. The method of the presentinvention realizes the foregoing objects by employing when forming thenon-parallel magnetically biased multiple magnetoresistive (MR) layermagnetoresistive (MR) sensor element: (1) a first thermal annealingmethod employing a first thermal annealing temperature, a first thermalannealing exposure time and a first extrinsic magnetic bias fieldstrength to form from a magnetically un-biased second magnetic biaslayer a magnetically biased second magnetic bias layer having a secondmagnetic bias field strength in a second magnetic bias directionnon-parallel to a first magnetic bias direction of a magnetically biasedfirst magnetic bias layer while simultaneously partially demagnetizingthe magnetically biased first magnetic bias layer to provide a partiallydemagnetized magnetically biased first magnetic bias layer having apartially demagnetized first magnetic bias field strength less than thefirst magnetic bias field strength; and (2) a second thermal annealingmethod employing a second thermal annealing temperature and a secondthermal annealing exposure time without a second magnetic bias field:(a) to form from the partially demagnetized magnetically biased firstmagnetic bias layer a remagnetized partially demagnetized first magneticbias layer having a remagnetized partially demagnetized first magneticbias field strength greater than the partially demagnetized firstmagnetic bias field strength; and (b) to form from the magneticallybiased second magnetic bias layer a further magnetically biased secondmagnetic bias layer having a further magnetized second magnetic biasfield strength greater than the second magnetic bias field strength.

Although the preferred embodiment of the present invention illustratesthe present invention within the context of fabricating within a mergedinductive magnetic write dual stripe magnetoresistive (DSMR) readmagnetic read-write head which is most likely to be employed withindigitally encoded magnetic data storage and retrieval an anti-parallelmagnetically biased dual stripe magnetoresistive (DSMR) sensor element,the method of the present invention may be employed in formingnon-parallel magnetically biased multiple magnetoresistive (MR) layermagnetoresistive (MR) sensor elements other than only anti-parallelmagnetically biased dual stripe magnetoresistive (DSMR) sensor elements.Such other non-parallel magnetically biased multiple magnetoresistive(MR) layer magnetoresistive (MR) sensor elements may include, but arenot limited to, non-parallel magnetically biased dual stripemagnetoresistive (DSMR) sensor elements other than anti-parallelmagnetically biased dual stripe magnetoresistive (DSMR) sensor elementsand non-parallel magnetically biased multiple magnetoresistive (MR)layer magnetoresistive layer magnetoresistive (MR) sensor elements otherthan dual stripe magnetoresistive (DSMR) sensor elements. The lattercategory may include, but is not limited to a dual spin valvemagnetoresistive (DSVMR) sensor element as is disclosed, for example andwithout limitation within Ohtsuka et al, within U.S. Pat. No. 5,859,753,as cited within the Description of the Related Art, the teachings of allof which related art are incorporated herein fully by reference.

Similarly, in a more fundamental sense, the present invention provides amethod for at least partially remagnetizing a partially demagnetizedmagnetic bias layer which may be employed within a magnetoresistive (MR)sensor element, typically under circumstances where the partiallydemagnetized magnetic bias layer has been partially demagnetizedincident to magnetically biasing an additional magnetic bias layerwithin the magnetoresistive (MR) sensor element or incident to someother demagnetizing incident experienced by the magnetoresistive (MR)sensor element. The magnetoresistive (MR) sensor element wherein thepartially demagnetized magnetic bias layer may be remagnetized may beselected from the group including but not limited to single stripemagnetoresistive (SSMR) sensor elements, dual stripe magnetoresistive(DSMR) sensor elements, spin valve magnetoresistive (SVMR) sensorelements and dual spin valve magnetoresistive (DSVMR) sensor elements.See, e.g., Dovek et al., U.S. Pat. No. 5,650,887, as cited within theDescription of the Related Art.

Finally, a non-parallel magnetically biased multiple magnetoresistive(MR) layer magnetoresistive (MR) sensor element fabricated in accordwith the present invention may be employed within a magnetic sensorwithin magnetic sensor applications including but not limited to digitalmagnetic sensor applications and analog magnetic sensor applicationsemploying magnetic heads including but not limited to merged inductivemagnetic write magnetoresistive (MR) read magnetic read-write heads,non-merged inductive magnetic write magnetoresistive (MR) read magneticread-write heads, and read only magnetoresistive (MR) read heads.

Referring now to FIG. 1 to FIG. 6, there is shown a series of schematicair bearing surface (ABS) view diagrams and schematic perspective viewdiagrams illustrating the results of progressive stages in fabricationof a merged inductive magnetic write dual stripe magnetoresistive (DSMR)read magnetoresistive (MR) sensor element having fabricated therein anominally anti-parallel non-parallel longitudinally magnetically biaseddual stripe magnetoresistive (DSMR) sensor element in accord a preferredembodiment of the present invention. Shown in FIG. 1 is a schematic airbearing surface (ABS) view diagram of the merged inductive magneticwrite dual stripe magnetoresistive (DSMR) read magnetoresistive (MR)sensor element at an early stage in its fabrication in accord with thepreferred embodiment of the present invention.

Shown in FIG. 1 is a substrate 10 having formed thereupon a blanketfirst shield layer 12 which in turn has formed thereupon a blanket firstnon-magnetic spacer layer 14. Within the preferred embodiment of thepresent invention with respect to the substrate 10, the blanket firstshield layer 12 and the blanket first non-magnetic spacer layer 14, thesubstrate 10, the blanket first shield layer 12 and the blanket firstnon-magnetic spacer layer 14 may be formed employing methods andmaterials as are conventional in the art of magnetoresistive (MR) sensorelement fabrication.

For example, although it is known in the art of magnetoresistive (MR)sensor element fabrication that substrates are typically formed fromnon-magnetic ceramic materials such as but not limited to oxides,nitrides, borides and carbides, as well as homogeneous and heterogeneousmixtures of oxides, nitrides, borides and carbides, for the preferredembodiment of the present invention, the substrate 10 is typically andpreferably formed from a non-magnetic aluminum oxide/titanium carbideceramic material. Preferably, the substrate 10 is formed with sufficientdimensions to allow the substrate 10 to be fabricated into a slideremployed within a magnetic head employed within a direct access storagedevice (DASD) magnetic data storage enclosure employed within digitallyencoded magnetic data storage and retrieval, although, as noted above, amagnetoresistive (MR) sensor element fabricated in accord with thepresent invention may be employed within other digital magnetic storageand transduction applications, as well as analog magnetic signal storageand transduction applications.

Similarly, although it is also known in the art of magnetoresistive (MR)sensor element fabrication that shield layers may be formed from any ofseveral soft magnetic materials, including but not limited tonickel-iron permalloy alloy soft magnetic materials and higher orderalloy soft magnetic materials incorporating nickel-iron permalloy alloysoft magnetic materials (ie: nickel-iron-rhodium soft magnetic materialsand nickel-iron-chromium soft magnetic materials), for the preferredembodiment of the present invention, the blanket first shield layer 12is preferably formed of a nickel-iron (80:20 w/w) permalloy alloy softmagnetic material. Typically and preferably, the blanket first shieldlayer 12 is formed to a thickness of from about 10000 to about 30000angstroms.

Finally, within the preferred embodiment of the present invention withrespect to the blanket first non-magnetic spacer layer 14, although theblanket first non-magnetic spacer layer 14 may be formed employingmethods and materials as are conventional in the art of magnetoresistive(MR) sensor element fabrication, including but not limited to chemicalvapor deposition (CVD) methods, plasma enhanced chemical vapordeposition (PECVD) methods and physical vapor deposition (PVD)sputtering methods through which may be formed non-magnetic spacerlayers of non-magnetic spacer materials including but not limited toconductor non-magnetic spacer materials and dielectric non-magneticspacer materials (such dielectric non-magnetic spacer materialsincluding but not limited to silicon oxide dielectric materials, siliconnitride dielectric materials, nitrogenated carbon dielectric materialsand aluminum oxide dielectric materials), for the preferred embodimentof the present invention, the blanket first non-magnetic spacer layer 14is preferably formed of an aluminum oxide non-magnetic dielectric spacermaterial deposited employing a physical vapor deposition (PVD)sputtering method, as is most common in the art of magnetoresistive (MR)sensor element fabrication. Preferably, the blanket first non-magneticspacer layer 14 so formed is formed to a thickness of from about 100 toabout 500 angstroms.

Although not completely illustrated within the schematic air-bearingsurface (ABS) view diagram of FIG. 1, there is also shown within FIG. 1formed upon the blanket first non-magnetic spacer layer 14 a patternedfirst magnetoresistive (MR) layer 16. Typically and preferably, thepatterned first magnetoresistive (MR) layer 16 is formed from amagnetoresistive (MR) material analogous or equivalent to the softmagnetic material employed for forming the blanket first shield layer12. Preferably, the patterned first magnetoresistive (MR) layer 16 isformed upon the blanket first non-magnetic spacer layer 14 from anickel-iron (80:20; w/w) permalloy alloy magnetoresistive material to athickness of from about 50 to about 200 angstroms, a length (i.e. longaxis or “easy” axis) of from about 0.3 to about 5 microns and a width(i.e. short axis of “hard” axis) of from about 0.3 to about 1.0 microns.

Finally, there is also shown within the schematic air-bearing surface(ABS) view diagram of FIG. 1 a pair of magnetically un-biased patternedfirst longitudinal magnetic bias layers 18 a and 18 b formed upon a pairof opposite ends of the long axis of the patterned firstmagnetoresistive (MR) layer 16 to define a first trackwidth TW1 of thepatterned first magnetoresistive (MR) layer 16. Preferably, the firsttrackwidth TW1 is from about 0.1 to about 3 microns. The pair ofmagnetically un-biased patterned first longitudinal magnetic bias layers18 a and 18 b may be formed of longitudinal magnetic bias materials asare known in the art of magnetoresistive (MR) sensor elementfabrication, including but not limited to: (1) antiferromagneticlongitudinal magnetic bias materials (such as but not limited toiron-manganese alloy longitudinal magnetic biasing materials,nickel-manganese longitudinal magnetic biasing materials,iridium-manganese alloy longitudinal magnetic biasing materials,platinum-manganese alloy longitudinal magnetic biasing materials,platinum-palladium-manganese alloy longitudinal magnetic biasingmaterials and additional related and higher order alloys thereof), aswell as; (2) permanent magnet longitudinal magnetic bias materials (suchas but not limited to platinum-cobalt alloy longitudinal magneticbiasing materials, higher order alloys incorporating platinum-cobaltalloy longitudinal magnetic biasing materials, cobalt-chromium alloylongitudinal magnetic biasing materials and rare earth alloylongitudinal magnetic biasing materials). Preferably, each of themagnetically un-biased patterned first longitudinal magnetic bias layers18 a and 18 b is formed of an antiferromagnetic longitudinal magneticbias material, preferably a nickel-manganese alloy (50:50, w/w)antiferromagnetic longitudinal magnetic bias material, preferably to athickness of from about 100 to about 300 angstroms each.

Although not illustrated within the schematic air bearing surface (ABS)view diagram of FIG. 1, there is typically and preferably also formedcoextensively upon the pair of magnetically un-biased patterned firstlongitudinal magnetic bias layers 18 a and 18 b a pair of patternedfirst conductor lead layers. Illustration of the pair of patterned firstconductor lead layers is omitted from the schematic air bearing surface(ABS) view diagram of FIG. 1, in order to provide clarity. Typically andpreferably, the pair of patterned first conductor lead layers may beformed simultaneously with the pair of magnetically un-biased patternedfirst longitudinal magnetic bias layers 18 a and 18 b while employing alift-off method. Typically and preferably, each patterned firstconductor lead layer within the pair of patterned first conductor leadlayers is formed to a thickness of from about 500 to about 1000angstroms while employing a conductor lead material conventional in theart of magnetoresistive (MR) sensor element fabrication, such aconductor lead material being selected from the group of conductor leadmaterials including but not limited to aluminum, aluminum alloy, copper,copper alloy, tungsten, tungsten alloy, tantalum, tantalum alloy, goldand gold alloy conductor lead materials, as well as laminates thereof.

Finally, although the schematic air-bearing surface (ABS) view diagramof FIG. 1 illustrates the pair of magnetically unbiased patterned firstlongitudinal magnetic bias layers 18 a and 18 b formed upon thepatterned first magnetoresistive layer 16, it is also feasible withinthe present invention that a pair of magnetically un-biased ormagnetically biased patterned first longitudinal magnetic biasinglayers, analogous to the pair of magnetically unbiased patterned firstlongitudinal magnetic bias layers 18 a and 18 b, either abuts or isformed beneath a patterned first magnetoresistive (MR) layer, such asthe patterned first magnetoresistive (MR) layer 16, provided that thepair of magnetically un-biased or magnetically biased patterned firstlongitudinal magnetic bias layers contacts a pair of opposite ends ofthe patterned first magnetoresistive (MR) layer to define a firsttrackwidth of the patterned first magnetoresistive (MR) layer.

Referring now to FIG. 2, there is shown a schematic air bearing surface(ABS) view diagram illustrating the results of further processing of themerged inductive magnetic write dual stripe magnetoresistive (DSMR) readmagnetoresistive (MR) sensor element whose schematic air bearing surface(ABS) view diagram is illustrated in FIG. 1. Shown in FIG. 2 is aschematic air bearing surface (ABS) view diagram of a merged inductivemagnetic write dual stripe magnetoresistive (DSMR) read magnetoresistive(MR) sensor element otherwise equivalent to the inductive magnetic writedual stripe magnetoresistive (DSMR) read magnetoresistive (MR) sensorelement whose schematic cross-sectional diagram is illustrated in FIG.1, but wherein the magnetically un-biased patterned first longitudinalmagnetic bias layers 18 a and 18 b are longitudinally magneticallybiased by thermal annealing within a first thermal annealing methodunder the influence of a first extrinsic magnetic bias field H1 tolongitudinally magnetically bias the pair of magnetically un-biasedpatterned first longitudinal magnetic bias layers 18 a and 18 b in adirection substantially parallel with an axis which separates the pairof magnetically un-biased patterned first longitudinal magnetic biaslayers 18 a and 18 b, thus forming from the pair of magneticallyun-biased patterned first longitudinal magnetic bias layers 18 a and 18b a pair of magnetically biased patterned first longitudinal magneticbiasing layers 18 a′ and 18 b′.

Although the preferred embodiment of the present invention illustratesthe longitudinal magnetic biasing of the pair of magnetically un-biasedpatterned first longitudinal magnetic bias layers 18 a′ and 18 b′ toform the pair of magnetically biased patterned first longitudinalmagnetic bias layers 18 a′ and 18 b′ by employing the first extrinsicmagnetic bias field H1 while employing the first thermal annealingmethod after forming the pair of magnetically un-biased patterned firstlongitudinal magnetic bias layers 18 a and 18 b, it is also feasiblewithin the method of the present invention that the magnetically biasedpatterned first longitudinal magnetic bias layers 18 a′ and 18 b′ may beformed directly incident to forming the otherwise magnetically un-biasedpatterned first longitudinal magnetic biasing layers 18 a and 18 bwithin the first extrinsic magnetic bias field Hi when originallyforming the pair of otherwise magnetically un-biased patterned firstlongitudinal magnetic bias layers 18 a′ and 18 b′.

Within the preferred embodiment of the present invention, themagnetically biased patterned first longitudinal magnetic bias layers 18a′ and 18 b′ are preferably formed employing the first thermal annealingmethod wherein the inductive magnetic write dual stripe magnetoresistive(DSMR) read magnetoresistive (MR) sensor element whose schematic airbearing surface (ABS) view diagram is illustrated in FIG. 1 is thermallyannealed within the first extrinsic magnetic bias field H1 of strengthfrom about 500 to about 2000 oersteds for a time period of from about 5to about 10 hours and a temperature of about 280 to about 300 degreescentigrade, under circumstances where the magnetically un-biasedpatterned first longitudinal magnetic bias layers 18 a and 18 b are eachformed of a nickel-manganese (50:50; w/w) antiferromagnetic longitudinalmagnetic bias material as is conventional in the art of magnetoresistive(MR) sensor element fabrication. Under such first thermal annealingconditions, it is expected that the pair of magnetically biasedpatterned first longitudinal magnetic bias layers 18 a′ and 18 b′ isfully magnetically saturated in a first magnetic bias direction with afirst magnetic bias field strength. More preferably, and although notspecifically illustrated within the schematic cross-sectional diagram ofFIG. 2, the magnetically biased patterned first longitudinal magneticbias layers 18 a′ and 18 b′ are preferably formed employing the firstthermal annealing method wherein the merged inductive write dual stripemagnetoresistive (DSMR) read magnetoresistive (MR) sensor element whoseschematic cross-sectional diagram is illustrated in FIG. 1, but overwhich is formed a patterned second magnetoresistive (MR) layer, isthermally annealed while employing the first thermal annealing methodemploying the first extrinsic magnetic bias field H1 employing the aboverecited thermal annealing conditions. Under such circumstances, thepatterned first magnetoresistive (MR) layer 16 and the patterned secondmagnetoresistive (MR) layer will typically, incident to theirsimultaneous thermal annealing, have correlating resistance andmagnetoresistance (MR) properties.

Although the schematic air-bearing surface (ABS) view diagram of FIG. 2implicitly illustrates the magnetically biased patterned firstlongitudinal magnetic biasing layers 18 a′ and 18 b′ as nominallycompletely aligned with a major axis which separates the pair ofmagnetically biased patterned first longitudinal magnetic bias layers 18a′ and 18 b′, it is understood by a person skilled in the art that themagnetically biased patterned first longitudinal magnetic bias layers 18a′ and 18 b′ will typically and preferably be only substantially alignedwith an acute divergent angle of up to about 60 degrees, and morepreferably from about 30 to about 50 degrees, from the major axis ofcomplete alignment. Such substantial alignment is typical incident tothermal annealing methods and magnetically assisted deposition methodsas are conventional in the art of magnetoresistive (MR) sensor elementfabrication, and such substantial alignment, rather than completealignment, provides optimal magnetoresistive (MR) properties to a dualstripe magnetoresistive (DSMR) sensor element.

Referring now to FIG. 3a, there is shown a schematic air bearing surface(ABS) view diagram illustrating the results of further processing of themerged inductive magnetic write dual stripe magnetoresistive (DSMR) readmagnetoresistive (MR) sensor element whose schematic air bearing surface(ABS) view diagram is illustrated in FIG. 2. Shown in FIG. 3a is aschematic air bearing surface (ABS) view diagram of a merged inductivemagnetic write dual stripe magnetoresistive (DSMR) read magnetoresistive(MR) sensor element otherwise equivalent to the merged inductivemagnetic write dual stripe magnetoresistive (MR) read magnetoresistive(MR) sensor element whose schematic air bearing surface (ABS) viewdiagram is illustrated in FIG. 2, but wherein: (1) there is formed uponthe pair of magnetically biased patterned first longitudinal magneticbiasing layers 18 a′ and 18 b′ and upon the first trackwidth TW1 of thepatterned first magnetoresistive (MR) layer 16 a blanket secondnon-magnetic spacer layer 20; (2) there is formed upon the blanketsecond non-magnetic spacer layer 20 a patterned second magnetoresistivelayer 22; and (3) there is formed upon the patterned secondmagnetoresistive layer 22 a pair of magnetically un-biased patternedsecond longitudinal magnetic bias layers 24 a and 24 b which define asecond trackwidth TW2 of the patterned second magnetoresistive (MR)layer 22. Preferably, the second trackwidth TW2 is of a width andalignment corresponding with the first trackwidth TW1.

Within the preferred embodiment of the present invention, the blanketsecond non-magnetic spacer layer 20 is preferably formed employingmethods and materials analogous or equivalent to the methods andmaterials preferably employed for forming the blanket first non-magneticspacer layer 14. Typically and preferably, the blanket secondnon-magnetic spacer layer 20 is formed of an aluminum oxide non-magneticdielectric spacer material formed to a thickness of from about 200 toabout 500 angstroms. Similarly, within the preferred embodiment of thepresent invention, the patterned second magnetoresistive layer 22 ispreferably formed employing methods, materials and dimensions analogousor equivalent to the methods, materials and dimensions employed forforming the patterned first magnetoresistive layer 16. Finally, withinthe preferred embodiment of the present invention, the pair ofmagnetically un-biased patterned second longitudinal magnetic biaslayers 24 a and 24 b is preferably formed employing methods, materialsand dimensions analogous or equivalent to the methods, materials anddimensions employed for forming the pair of magnetically un-biasedpatterned first longitudinal magnetic bias layers 18 a′ and 18 b′. Inparticular, the pair of magnetically un-biased patterned secondlongitudinal magnetic bias layers 24 a and 24 b and the pair ofmagnetically un-biased patterned first longitudinal magnetic bias layers18 a and 18 b are preferably but not necessarily formed of a singlelongitudinal magnetic biasing material. Analogously with themagnetically un-biased patterned first longitudinal magnetic biasinglayers 18 a and 18 b, and similarly also not illustrated within theschematic air bearing surface (ABS) view diagram of FIG. 3a, the pair ofmagnetically un-biased patterned second longitudinal magnetic biaslayers 24 a and 24 b also preferably has formed and aligned thereupon,while similarly also preferably employing a lift off method, a pair ofpatterned second conductor lead layers formed employing materials anddimensions analogous or equivalent to the materials and dimensionsemployed for forming the pair of patterned first conductor lead layers.

Referring now to FIG. 3b, there is shown a schematic perspective viewdiagram corresponding with the schematic cross-sectional diagram of FIG.3a. Shown in FIG. 3b is the patterned first magnetoresistive (MR) layer16 having formed upon a pair of its opposite ends the pair ofmagnetically biased patterned first longitudinal magnetic bias layers 18a′ and 18 b′ which are preferably formed fully saturated in a firstmagnetic bias direction with a first magnetic bias field strength.Similarly, there is also shown within FIG. 3b the patterned secondmagnetoresistive (MR) layer 22 having formed and aligned thereupon thepair of magnetically un-biased patterned second longitudinal magneticbias layers 24 a and 24 b. All other layers within the merged inductivemagnetic write dual stripe magnetoresistive (DSMR) read magnetoresistive(MR) sensor element whose schematic air bearing surface (ABS) viewdiagram is illustrated in FIG. 3a have been omitted for clarity.

Referring now to FIG. 4a, there is shown a schematic air bearing surface(ABS) view diagram illustrating the results of further processing of themerged inductive magnetic write dual stripe magnetoresistive (DSMR) readmagnetoresistive (MR) sensor element whose schematic air bearing surface(ABS) view diagram is illustrated in FIG. 3a. Shown in FIG. 4a is aschematic air bearing surface (ABS) view diagram of a merged inductivemagnetic write dual stripe magnetoresistive (DSMR) read magnetoresistive(MR) sensor element otherwise equivalent to the merged inductivemagnetic write dual stripe magnetoresistive (DSMR) read magnetoresistive(MR) sensor element whose schematic air bearing surface (ABS) viewdiagram is illustrated in FIG. 3a, but wherein the magneticallyun-biased patterned second longitudinal magnetic biasing layers 24 a and24 b have been longitudinally magnetically biased while employing asecond thermal annealing method employing a second extrinsic magneticbias field H2 nominally anti-parallel to the first extrinsic magneticbias field H1 as illustrated within the schematic air bearing surface(ABS) view diagram of FIG. 2, to provide the magnetically biasedpatterned second longitudinal magnetic bias layers 24 a′ and 24 b′.

Within the preferred embodiment of the present invention, themagnetically un-biased patterned second longitudinal magnetic biaslayers 24 a and 24 b are longitudinally magnetically biasedsubstantially nominally anti-parallel with respect to the magneticallybiased patterned first longitudinal magnetic biasing layers 18 a′ and 18b′ as illustrated in FIG. 2, while employing the second thermalannealing method which employs a second thermal annealing temperatureand a second thermal annealing exposure time, in conjunction with thesecond extrinsic magnetic bias field H2 of appropriate magnetic fieldstrength, such that the pair of magnetically un-biased patterned secondlongitudinal magnetic biasing layers 24 a and 24 b is longitudinallymagnetically biased to form the pair of magnetically biased patternedsecond longitudinal magnetic bias layers 24 a′ and 24 b′ whilesubstantially but not completely de-magnetizing the pair of magneticallybiased patterned first longitudinal magnetic bias layers 18 a′ and 18 b′which then form a pair of partially demagnetized magnetically biasedpatterned first longitudinal magnetic bias layers 18 a′ and 18 b″, asillustrated within the schematic air bearing surface (ABS) view diagramof FIG. 4a.

For the preferred embodiment of the present invention when both the pairof magnetically biased patterned first longitudinal magnetic bias layers18 a′ and 18 b′, as well as the pair of magnetically un-biased patternedsecond longitudinal magnetic bias layers 24 a and 24 b, are formed of anickel-manganese alloy (50:50, w/w) antiferromagnetic longitudinalmagnetic bias material, the pair of magnetically un-biased patternedsecond longitudinal magnetic biasing layers 24 a and 24 b is preferablythermally annealed at the second thermal annealing temperature of fromabout 250 to about 275 degrees centigrade for a second thermal annealingexposure time period of from about 0.5 to about 1.5 hours within thesecond extrinsic magnetic bias field H2 of strength about 1000 to about2000 oersteds. Preferably, each of the first thermal annealing methodand the second thermal annealing method also employs a nitrogenatmosphere.

Within the present invention, it is preferred that the pair ofmagnetically biased patterned first longitudinal magnetic bias layers 18a′ and 18 b′ be substantially demagnetized when forming the pair ofpartially demagnetized patterned first longitudinal magnetic bias layers18 a″ and 18 b″ to provide the pair of partially demagnetized patternedfirst longitudinal magnetic bias layers with a partially demagnetizedfirst magnetic bias field strength of no less than about 25 to about 30percent (more preferably from about 30 to about 50 percent) of the firstmagnetic bias field strength, while still maintaining the first magneticbias field direction, when forming the pair of partially demagnetizedmagnetically biased patterned first longitudinal magnetic bias layers 18a″ and 18 b″ incident to forming the pair of magnetically biasedpatterned second longitudinal magnetic bias layers 24 a′ and 24 b′ fromthe pair of magnetically unbiased patterned second longitudinal magneticbias layers 24 a and 24 b. Thus, within the present invention, there isbalanced at an appropriate second thermal annealing temperature, secondthermal annealing exposure time and second extrinsic magnetic bias fieldH2 strength a magnetization of the pair of magnetically un-biasedpatterned second longitudinal magnetic bias layers 24 a and 24 b incomparison with a demagnetization of the pair of magnetically biasedpatterned first longitudinal magnetic bias layers 18 a′ and 18 b′.

Similarly, although not specifically illustrated within the preferredembodiment of the present invention, within the present invention,generally, the extrinsic first magnetic bias field H1 and the extrinsicsecond magnetic bias field H2 need only be non-parallel, rather thananti-parallel.

Referring now to FIG. 4b, there is shown a schematic perspective viewdiagram corresponding with the schematic cross-sectional diagram of FIG.4a. Shown in FIG. 4b is the patterned first magnetoresistive (MR) layer16 having formed upon a pair of its opposite ends the pair of partiallydemagnetized magnetically biased patterned first longitudinal magneticbias layers 18 a″ and 18 b″. Similarly, there is also shown within FIG.4b the patterned second magnetoresistive layer 22 having formed andaligned upon a pair of its opposite ends the pair of magnetically biasedpatterned second longitudinal magnetic bias layers 24 a′ and 24 b′. Asis illustrated within the schematic perspective view diagram of FIG. 4b,the pair of magnetically biased patterned second longitudinal magneticbiasing layers 24 a′ and 24 b′ is partially magnetized while the pair ofpartially demagnetized magnetically biased patterned first longitudinalmagnetic bias layers 18 a″ and 18 b″ is not completely demagnetized. Allother layers within the merged inductive magnetic write dual stripemagnetoresistive (DSMR) read magnetoresistive (MR) sensor element whoseschematic air bearing surface (ABS) view diagram is illustrated in FIG.4a have been omitted for clarity.

Similarly, although both FIG. 4a and FIG. 4b illustrate the results ofthe second thermal annealing method for forming the pair of magneticallybiased patterned second longitudinal magnetic biasing layers 24 a′ and24 b′ as occurring immediately after forming the pair of magneticallyunbiased patterned second longitudinal magnetic biasing layers 24 a and24 b upon the patterned second magnetoresistive (MR) layer 22, withinthe method of the present invention, the second thermal annealing mayoften preferably be undertaken at a later stage in processing of themerged inductive magnetic write dual stripe magnetoresistive (DSMR) readmagnetoresistive (MR) sensor element whose schematic air bearing surface(ABS) view diagram is illustrated in FIG. 4a and whose schematicperspective view diagram is illustrated in FIG. 4b. For example, andwithout limitation, the second thermal annealing may be undertaken afterwrite element structures are formed within the merged inductive magneticwrite dual stripe magnetoresistive (DSMR) read magnetoresistive (MR)sensor element whose schematic air bearing surface (ABS) view diagram isillustrated in FIG. 4a and whose schematic perspective view diagram isillustrated in FIG. 4b. Under such circumstances, the second thermalannealing may, for example, thermally anneal and stabilize a magneticwrite pole layer and a magnetic write coil layer.

Referring now to FIG. 5a, there is shown a schematic air bearing surface(ABS) view diagram illustrating the results of further processing of themerged inductive magnetic write dual stripe magnetoresistive (DSMR) readmagnetoresistive (MR) sensor element whose schematic air bearing surface(ABS) view diagram is illustrated in FIG. 4a.

Shown in FIG. 5a is a schematic air bearing surface (ABS) view diagramof a merged inductive magnetic write dual stripe magnetoresistive (DSMR)read magnetoresistive (MR) sensor element otherwise equivalent to themerged inductive magnetic write dual stripe magnetoresistive (DSMR) readmagnetoresistive (MR) sensor element whose schematic air bearing surface(ABS) view diagram is illustrated in FIG. 4a, but wherein the mergedinductive magnetic write dual stripe magnetoresistive (DSMR) readmagnetoresistive (MR) sensor element has been thermally annealed whileemploying a third thermal annealing method employing a third thermalannealing temperature and a third thermal annealing exposure timewithout a third extrinsic magnetic bias field to: (1) form from thepartially demagnetized magnetically biased patterned first longitudinalmagnetic bias layers 18 a″ and 18 b″ a corresponding pair ofremagnetized partially demagnetized magnetically biased patterned firstlongitudinal magnetic bias layers 18 ″ and 18 b″ having a remagnetizedpartially demagnetized first magnetic bias field strength in the firstmagnetic bias direction and greater than the partially demagnetizedfirst magnetic bias field strength; and (2) form from the pair ofmagnetically biased patterned second longitudinal magnetic bias layers24 a′ and 24 b′ a pair of further magnetically biased patterned secondlongitudinal magnetic bias layers 24 a″ and 24 b″ having a furthermagnetized second magnetic bias field strength in the second magneticbias direction and greater than the second magnetic bias field strength.

Within the preferred embodiment of the present invention with respect tothe third thermal annealing method, the third thermal annealing methodpreferably employs a third thermal annealing temperature of at leastabout 250 degrees centigrade and preferably from about 250 to about 300degrees centigrade and a third thermal exposure time of at least about 3hours, preferably from about 4 to about 10 hours.

Referring now to FIG. 5b, there is shown a schematic perspective viewdiagram corresponding with the schematic air bearing surface (ABS) viewdiagram of FIG. 5a. Shown in FIG. 5b is the patterned firstmagnetoresistive (MR) layer 16 having formed upon a pair of its oppositeends the pair of remagnetized partially demagnetized magnetically biasedpatterned first longitudinal magnetic bias layers 18 a′″and 18 b′″.Similarly, there is also shown within FIG. 5b the patterned secondmagnetoresistive layer 22 having formed and aligned upon a pair of itsopposite ends the pair of further magnetically biased patterned secondlongitudinal magnetic bias layers 24 a″and 24 b″. As is illustratedwithin the schematic perspective view diagram of FIG. 5b, the pair ofremagnetized partially demagnetized magnetically biased patterned firstlongitudinal magnetic bias layers 18 a′″and 18 b′″ is remagnetized witha remagnetized partially demagnetized first magnetic bias field strengthin the first magnetic bias direction and greater than the partiallydemagnetized first magnetic bias field strength of the pair of partiallydemagnetized magnetically biased patterned first longitudinal magneticbias layers 18 a″ and 18 b″ as is illustrated in the schematicperspective view diagram of FIG. 4b. Similarly, the further magneticallybiased patterned second longitudinal magnetic bias layers 24 a″ and 24b″ are, as illustrated within the schematic perspective view diagram ofFIG. 5b, further magnetized in the second magnetic bias direction with afurther magnetized second magnetic bias field strength greater than thesecond magnetic bias field strength of the pair of magnetically biasedpatterned second longitudinal magnetic bias layers 24 a′ and 24 b′ asillustrated within the schematic perspective view diagram of FIG. 4b.All other layers within the merged inductive magnetic write dual stripemagnetoresistive (DSMR) read magnetoresistive (MR) sensor element whoseschematic air bearing surface (ABS) view diagram is illustrated in FIG.5a have been omitted for clarity.

Referring now to FIG. 6, there is shown a schematic air bearing surface(ABS) view diagram illustrating the results of further processing of themerged inductive magnetic write dual stripe magnetoresistive (MR) readmagnetoresistive (MR) sensor element whose schematic air bearing surface(ABS) view diagram is illustrated in FIG. 5a.

Shown in FIG. 6 is a schematic air bearing surface (ABS) view diagram ofa merged inductive magnetic write dual stripe magnetoresistive (DSMR)read magnetoresistive (MR) sensor element otherwise equivalent to themerged inductive magnetic write dual stripe magnetoresistive (DSMR) readmagnetoresistive (MR) sensor element whose schematic air bearing surface(ABS) view diagram is illustrated in FIG. 5a, but wherein: (1) there isformed upon the pair of further magnetically biased patterned secondlongitudinal magnetic bias layers 24 b″ and the second trackwidth TW2 ofthe patterned second magnetoresistive layer 22 a blanket thirdnon-magnetic spacer layer 26; (2) there is formed upon the blanket thirdnon-magnetic spacer layer 26 a blanket second shield layer 28 whichsimultaneously serves as a blanket first magnetic inductor write polelayer; (3) there is formed upon the blanket second shield layer 28 ablanket fourth non-magnetic write gap filling spacer layer 30; and (4)there is formed upon the blanket fourth non-magnetic write gap fillingspacer layer 30 a patterned second magnetic inductor write pole layer32.

Within the preferred embodiment of the present invention, the blanketthird non-magnetic spacer layer 26 is preferably formed employingmethods, materials and dimensions analogous or equivalent to themethods, materials and dimensions employed for forming the blanket firstnon-magnetic spacer layer 14. Similarly, within the preferred embodimentof the present invention the blanket second shield layer 28 ispreferably formed employing methods, materials and dimensions analogousor equivalent to the methods, materials and dimensions employed forforming the blanket first shield layer 12. Yet similarly, for thepreferred embodiment of the present invention, the blanket fourthnon-magnetic write gap filling spacer layer 30 is preferably formedemploying methods and materials analogous or equivalent to the methodsand materials employed for forming the blanket third non-magnetic spacerlayer 26, the blanket second non-magnetic spacer layer 20 and theblanket first non-magnetic spacer layer 14. Preferably, the blanketfourth non-magnetic write gap filling spacer layer 30 is formed to athickness of from about 500 to about 3000 angstroms of an aluminum oxidenon-magnetic dielectric spacer material. Finally, within the preferredembodiment of the present invention, the patterned second magneticinductor write pole layer 32 is preferably formed employing methodsmaterials and thickness dimensions analogous or equivalent to themethods, materials and thickness dimensions employed for forming theblanket second shield layer 28, but of a narrower width dimension in therange of from about 0.1 to about 3 microns to correspond with the firsttrackwidth TW1 of the patterned first magnetoresistive layer 16 and thesecond trackwidth TW2 of the patterned second magnetoresistive (MR)layer 22.

Upon forming the merged inductive magnetic write dual stripemagnetoresistive (DSMR) read magnetoresistive (MR) sensor element whoseschematic air bearing surface (ABS) view diagram is illustrated in FIG.6, there is formed a merged inductive magnetic write dual stripemagnetoresistive (DSMR) read magnetoresistive (MR) sensor element withenhanced magnetic bias profile uniformity within the trackwidth of themerged inductive magnetic write dual stripe magnetoresistive (DSMR) readmagnetoresistive (MR) sensor element. The merged inductive magneticwrite dual stripe magnetoresistive (MR) read magnetoresistive (MR)sensor element of the present invention realizes the foregoing object byemploying an anti-parallel longitudinal magnetic biasing of two pair ofpatterned longitudinal magnetic biasing layers which longitudinallymagnetically bias a pair of patterned magnetoresistive (MR) layerswithin the merged inductive magnetic write dual stripe magnetoresistive(DSMR) read magnetoresistive (MR) sensor element. The two of pairpatterned longitudinal magnetic biasing layers are preferably althoughnot necessarily formed of a single longitudinal magnetic biasingmaterial. Similarly, the method of the present invention employs whenforming a pair of magnetically biased patterned second longitudinalmagnetic bias layers upon a patterned second magnetoresistive (MR) layera two step thermal annealing method comprising: (1) a first thermalannealing method employing a first thermal annealing temperature, afirst thermal annealing exposure time and a first an extrinsic magneticbias field strength such that a pair of magnetically un-biased patternedsecond longitudinal magnetic bias layers is longitudinally magneticallybiased while de-magnetizing a pair of magnetically biased patternedfirst longitudinal magnetic bias layers which longitudinallymagnetically bias a patterned first magnetoresistive (MR) layer in adirection anti-parallel to the patterned second magnetoresistive (MR)layer; and (2) a second thermal annealing method employing a secondthermal annealing temperature and a second thermal annealing exposuretime without a second extrinsic magnetic bias field to further magnetizethe pair of magnetically biased patterned second magnetic bias layerswhen forming a pair of further magnetically biased patterned secondmagnetic bias layers and remagnetize the pair of partially demagnetizedmagnetically biased patterned first longitudinal magnetic bias layerswhen forming a pair of remagnetized partially demagnetized patternedfirst longitudinal magnetic bias layers.

EXAMPLE

In order to illustrate the value and operation of the present invention,there was fabricated a non-parallel anti-parallel longitudinallymagnetically biased dual stripe magnetoresistive (DSMR) sensor elementin accord with the preferred embodiment of the present invention. Theanti-parallel longitudinally magnetically biased dual stripemagnetoresistive (DSMR) sensor element employed a patterned firstmagnetoresistive (MR) layer and a patterned second magnetoresistive (MR)layer each formed of a nickel-iron (80:20; w/w) permalloymagnetoresistive (MR) material formed to a thickness of about 100angstroms, a length (long axis) of about 0.8 microns and a width (shortaxis) of about 0.4 microns, where the patterned first magnetoresistive(MR) layer had formed upon a pair of its opposite ends separated by thelong axis a pair of magnetically un-biased patterned first longitudinalmagnetic bias layers and the patterned second magnetoresistive (MR)layer had formed upon a pair of its opposite ends separated by the longaxis a pair of magnetically un-biased patterned second longitudinalmagnetic bias layers. Both the pair of magnetically un-biased patternedfirst longitudinal magnetic bias layers and the pair of magneticallyun-biased patterned second longitudinal magnetic bias layers were formedof a nickel-manganese (50:50; w/w) antiferromagnetic longitudinalmagnetic bias material formed to a thickness of about 300 angstroms andpositioned to provide a trackwidth of the patterned firstmagnetoresistive (MR) layer or the patterned second magnetoresistive(MR) layer of about 0.8 microns.

In accord with the preferred embodiment of the present invention, thepair of magnetically un-biased patterned first longitudinal magneticbias layers was magnetically biased to form therefrom a pair ofmagnetically biased patterned first longitudinal magnetic bias layersprior to forming upon the patterned second magnetoresistive (MR) layerthe pair of magnetically un-biased patterned second longitudinalmagnetic bias layers, through thermal annealing while employing a firstthermal annealing method employing a first thermal annealing temperatureof about 300 degrees centigrade, a first thermal annealing exposure timeof about 8 hours and a first magnetic bias field strength of about 2000oersteds directed at an acute angle of about 30 degrees with respect tothe long (i.e. easy) axis of either the patterned first magnetoresistive(MR) layer or the patterned second magnetoresistive (MR) layer. Afterthe first thermal annealing, measurements of: (1) an exchange biasfield, Hex, between the patterned first magnetoresistive (MR) layer andthe magnetically biased patterned first longitudinal magnetic biaslayers; and (2) coercivity field, Hc, of the patterned firstmagnetoresistive (MR) layer were obtained employing methods as areconventional in the art of magnetoresistive (MR) sensor elementfabrication.

After forming the pair of magnetically un-biased patterned secondlongitudinal magnetic bias layers upon the pair of opposite ends of thepatterned second magnetoresistive (MR) layer, there was then thermallyannealed the dual stripe magnetoresistive (DSMR) sensor element whileemploying a second thermal annealing method which employed a secondthermal annealing temperature of about 270 degrees centigrade, a secondthermal annealing exposure time of about 0.5 hours and a secondextrinsic magnetic bias field strength of about 2000 oersteds directedanti-parallel to the first extrinsic magnetic bias field direction,which second thermal annealing: (1) partially demagnetized the pair ofmagnetically biased patterned first magnetic bias layers to form acorresponding pair of partially demagnetized magnetically biasedpatterned first magnetic bias layers; and (2) magnetized the pair ofmagnetically un-biased patterned second magnetic bias layer to form acorresponding pair of magnetically biased patterned second magnetic biaslayers. There was then measured: (1) a first exchange field, Hex,strength between the pair of partially demagnetized magnetically biasedpatterned first longitudinal magnetic bias layers and the patternedfirst magnetoresistive (MR) layer; (2) a first coercivity field, Hc, ofthe patterned first magnetoresistive (MR) layer; (3) a second exchangefield, Hex, strength between the pair of magnetically biased patternedsecond longitudinal magnetic bias layers and the patterned secondmagnetoresistive (MR) layer; and (4) a second coercivity field, Hc, ofthe patterned second magnetoresistive (MR) layer.

There was then thermally annealed the dual stripe magnetoresistive(DSMR) sensor element while employing a third thermal annealing methodemploying a third thermal annealing temperature of about 300 degreescentigrade for a third thermal annealing time period of about 0.5 hoursin absence of a third extrinsic magnetic bias field to: (1) form fromthe partially demagnetized magnetically biased patterned firstlongitudinal magnetic bias layers a pair of remagnetized partiallydemagnetized patterned first longitudinal magnetic bias layers; and (2)form from the pair of magnetically biased patterned second longitudinalmagnetic bias layers a pair of further magnetically biased pattern edsecond longitudinal magnetic bias layers. There was then again measured:(1) a first exchange field, Hex, strength between the pair ofremagnetized partially demagnetized magnetically biased patterned firstlongitudinal magnetic bias layers and the patterned firstmagnetoresistive (MR) layer; (2) a first coercivity field, Hc, of thepatterned first magnetoresistive (MR) layer; (3) a s econd exchangefield, Hex, strength between the pair of further magnetically biasedpatterned second longitudinal magnetic bias layers and the patternedsecond magnetoresistive (MR) layer; and (4) a second coercivity field,Hc, of the patterned second magnetoresistive (MR) layer.

Measured results for the exchange field, Hex, strengths and thecoercivity field, Hc, strengths, as defined above, are reported withinTable I, as follows.

TABLE I Annealing Conditions Hex (Oe) Hc (Oe) Hex/Hc For FirstMagnetoresistive (MR) Layer 1^(st) - 300 C/8 hr/2000 Oe 210 90 2.32^(nd) - 270 C/0.5 hr/−2000 Oe 50 90 0.6 3^(rd) - 300 C/0.5 hr/0.0 Oe170 90 1.9 For Second Magnetoresistive (MR) Layer 2^(nd) - 270 C/0.5hr/−2000 Oe −20 60 −0.3 3^(rd) - 300 C/0.5 hr/0.0 Oe −130 100 −1.3

As is seen from review of the data reported within Table I, there isobserved, in accord with that which is disclosed within the preferredembodiment of the present invention and claimed within the claims whichfollow: (1) a significant recovery of demagnetization of an exchangebias field for a pair of partially demagnetized magnetically biasedpatterned first longitudinal magnetic bias layers with respect to apatterned first magnetoresistive (MR) layer; and (2) an additionalexchange biasing of a pair of magnetically biased patterned secondlongitudinal magnetic bias layers with respect to a patterned secondmagnetoresistive (MR) layer, when an anti-parallel magnetic biased dualstripe magnetoresistive (DSMR) sensor element having formed therein thepair of partially demagnetized patterned first longitudinal magneticbias layers and the pair of magnetically biased patterned secondmagnetic bias layers is thermally annealed absent an extrinsic magneticbias field.

As is understood by a person skilled in the art, the preferredembodiment and example of the present invention are illustrative of thepresent invention rather than limiting of the present invention.Revisions and modifications may be made to materials, structures anddimensions through which is provided a non-parallel magnetically biasedmultiple magnetoresistive (MR) layer magnetoresistive (MR) sensorelement such as the dual stripe magnetoresistive (DSMR) sensor elementformed in accord with the preferred embodiment of the present inventionwhile still providing a non-parallel magnetically biased multiplemagnetoresistive (MR) layer magnetoresistive (MR) sensor element inaccord with the spirit and scope of the present invention, as defined bythe following claims.

What is claimed is:
 1. A method for remagnetizing a partiallydemagnetized magnetic bias layer within a multiple magnetoresistive (MR)layer magnetoresistive (MR) sensor element comprising: providing asubstrate; forming over the substrate a first magnetoresistive (MR)layer having formed there on contacting the first magnetoresistive (MR)layer, a magnetically biased first magnetic bias layer having a firstmagnetic bias field strength and a first magnetic bias direction;demagnetizing partially the magnetically biased first magnetic biaslayer to form a partially demagnetized first magnetic bias layer havinga partially demagnetized first magnetic bias field strength less thanthe first magnetic bias field strength; and remagnetizing the partiallydemagnetized first magnetic bias layer to form a remagnetized partiallydemagnetized first magnetic bias layer having a remagnetized partiallydemagnetized first magnetic bias field strength greater than thepartially demagnetized first magnetic bias field strength by annealingthermally the partially demagnetized first magnetic bias layer inabsence of a magnetic bias field.
 2. The method of claim 1 wherein theremagnetized partially demagnetized first magnetic bias layer isremagnetized by thermal annealing the partially demagnetized firstmagnetic bias layer in absence of the magnetic bias field but inpresence of a second magnetoresistive (MR) layer having a secondmagnetic bias direction non-parallel with the first magnetic biasdirection.
 3. The method of claim 1 wherein the magnetically biasedfirst magnetic bias layer is formed from a first magnetic bias materialselected from the group consisting of antiferromagnetic magnetic biasmaterials and permanent magnet magnetic bias materials.
 4. The method ofclaim 1 wherein the partially demagnetized first magnetic bias layer hasa partially demagnetized first magnetic bias field strength of fromabout 25 to about 50 percent of the first magnetic bias field strength.5. The method of claim 1 wherein the multiple magnetoresistive (MR)layer magnetoresistive (MR) sensor element is selected from the groupconsisting of dual stripe magnetoresistive (DSMR) sensor elements, spinvalve magnetoresistive (SVMR) sensor elements and dual spin valvemagnetoresistive (DSVMR) sensor elements.
 6. A method for forming amagnetoresistive (MR) sensor element comprising: providing a substrate;forming over the substrate a first magnetoresistive (MR) layer; formingcontacting the first magnetoresistive (MR) layer a magnetically biasedfirst magnetic bias layer, the magnetically biased first magnetic biaslayer being biased in a first magnetic bias direction with a firstmagnetic bias field strength; forming separated from the firstmagnetoresistive (MR) layer by a spacer layer a second magnetoresistive(MR) layer; forming contacting the second magnetoresistive (MR) layer amagnetically un-biased second magnetic bias layer; biasing through useof a first thermal annealing method employing a first thermal annealingtemperature, a first thermal annealing exposure time and a firstextrinsic magnetic bias field the magnetically un-biased second magneticbias layer to form a magnetically biased second magnetic bias layerhaving a second magnetic bias field strength in a second magnetic biasdirection non-parallel to the first magnetic bias direction whilesimultaneously partially demagnetizing the magnetically biased firstmagnetic bias layer to provide a partially demagnetized magneticallybiased first magnetic bias layer having a partially demagnetized firstmagnetic bias field strength less than the first magnetic bias fieldstrength; and annealing thermally through use of a second thermalannealing employing a second thermal annealing temperature and a secondthermal annealing exposure time without a second magnetic bias field:the partially demagnetized magnetically biased first magnetic bias layerto form a remagnetized partially demagnetized first magnetic bias layerhaving a remagnetized partially demagnetized first magnetic bias fieldstrength greater than the partially demagnetized first magnetic biasfield strength; and the magnetically biased second magnetic bias layerto form a further magnetically biased second magnetic bias layer havinga further magnetized second magnetic bias field strength greater thanthe second magnetic bias field strength.
 7. The method of claim 6wherein the magnetoresistive (MR) sensor element is employed within amagnetic head selected from the group consisting of merged inductivemagnetic write magnetoresistive (MR) read magnetic read-write heads,non-merged inductive magnetic write magnetoresistive (MR) read magneticread-write heads and magnetoresistive (MR) read only heads.
 8. Themethod of claim 6 wherein the magnetically biased first magnetic biaslayer and the magnetically un-biased second magnetic bias layer areformed of separate magnetic bias materials selected from the groupconsisting of antiferromagnetic magnetic bias materials and permanentmagnet magnetic bias materials.
 9. The method of claim 6 wherein themagnetically biased first magnetic bias layer and the magneticallyun-biased second magnetic bias layer are formed of a single magneticbias material selected from the group consisting of antiferromagneticmagnetic bias materials and permanent magnet magnetic bias materials.10. The method of claim 9 wherein: the single magnetic biasing materialis a nickel-manganese alloy (50:50, w/w) antiferromagnetic magneticbiasing material; the first thermal annealing temperature is from about250 to about 275 degrees centigrade; the first thermal annealingexposure time is from about 0.5 to about 1.5 hours; a first extrinsicmagnetic bias field strength is from about 1000 to about 2000 oersteds;the second thermal annealing temperature is from about 250 to about 300degrees centigrade; and the second thermal annealing exposure time isfrom about 3 to about 10 hours.
 11. The method of claim 6 wherein thepartially demagnetized magnetically biased first magnetic bias layer isdemagnetized to the partially demagnetized first magnetic bias fieldstrength which is from about 25 to about 50 percent of the firstmagnetic bias field strength.
 12. A method for forming an anti-parallelmagnetically biased dual stripe magnetoresistive (DSMR) sensor elementcomprising: providing a substrate; forming over the substrate apatterned first magnetoresistive (MR) layer; forming contacting a pairof opposite ends of the patterned first magnetoresistive (MR) layer apair of magnetically biased patterned first longitudinal magnetic biaslayers which defines a first trackwidth of the patterned firstmagnetoresistive (MR) layer, the pair of magnetically biased patternedfirst longitudinal magnetic bias layers being biased with a firstmagnetic bias field strength in a first longitudinal magnetic biasdirection substantially parallel with an axis of the patterned firstmagnetoresistive (MR) layer which separates the pair of patterned firstlongitudinal magnetic bias layers; forming separated from the patternedfirst magnetoresistive (MR) layer by a non-magnetic spacer layer apatterned second magnetoresistive layer; forming contacting a pair ofopposite ends of the patterned second magnetoresistive (MR) layer a pairof magnetically un-biased patterned second longitudinal magnetic biaslayers which defines a second trackwidth of the patterned secondmagnetoresistive (MR) layer; biasing through use of a first thermalannealing method employing a first thermal annealing temperature, afirst thermal annealing exposure time and a first extrinsic magneticbias field the pair of magnetically un-biased patterned secondlongitudinal magnetic bias layers to form a pair of magnetically biasedpatterned second longitudinal magnetic bias layers having a secondmagnetic bias field strength in a second magnetic bias directionanti-parallel to the first magnetic bias direction while simultaneouslypartially demagnetizing the pair of magnetically biased patterned firstlongitudinal magnetic bias layers to provide a pair of partiallydemagnetized magnetically biased patterned first longitudinal magneticbias layers having a partially demagnetized first magnetic bias fieldstrength less than the first magnetic bias field strength; and annealingthermally through use of a second thermal annealing method employing asecond thermal annealing temperature and a second thermal annealingexposure time without a second magnetic bias field: the pair ofpartially demagnetized magnetically biased patterned first longitudinalmagnetic bias layers to form a pair of remagnetized partiallydemagnetized patterned first longitudinal magnetic bias layers having aremagnetized partially demagnetized first magnetic bias field strengthgreater than the partially demagnetized first magnetic bias fieldstrength; and the pair of magnetically biased patterned secondlongitudinal magnetic bias layers to form a pair of further magneticbiased patterned second longitudinal magnetic bias layers having afurther magnetized second magnetic bias field strength greater than thesecond magnetic bias field strength.
 13. The method of claim 12 whereinthe anti-parallel magnetically biased dual stripe magnetoresistive(DSMR) sensor element is employed within a magnetic head selected fromthe group consisting of merged inductive magnetic write magnetoresistive(MR) read magnetic read-write heads, non-merged inductive magnetic writemagnetoresistive (MR) read magnetic read-write heads andmagnetoresistive (MR) read only heads.
 14. The method of claim 12wherein the pair of magnetically biased patterned first longitudinalmagnetic bias layers and the pair of magnetically un-biased patternedsecond longitudinal magnetic bias layers are formed of separatelongitudinal magnetic bias materials selected from the group consistingof antiferromagnetic longitudinal magnetic bias materials and permanentmagnet longitudinal magnetic bias materials.
 15. The method of claim 12wherein the pair of magnetically biased patterned first longitudinalmagnetic biasing layers and the pair of magnetically un-biased patternedsecond longitudinal magnetic biasing layers are formed of a singlelongitudinal magnetic bias material selected from the group consistingof antiferromagnetic longitudinal magnetic bias materials and permanentmagnet longitudinal magnetic bias materials.
 16. The method of claim 15wherein: the single longitudinal magnetic bias material is annickel-manganese alloy (50:50, w/w) antiferromagnetic longitudinalmagnetic bias material; the first thermal annealing temperature is fromabout 250 to about 275 degrees centigrade; the first thermal annealingexposure time is from about 0.5 to about 1.5 hours; a first extrinsicmagnetic bias field strength is from about 1000 to about 2000 oerstedsthe second thermal annealing temperature is from about 250 to about 300degrees centigrade; and the second thermal annealing temperature is fromabout 3 to about 10 hours.
 17. The method of claim 12 wherein the pairof partially demagnetized magnetically biased patterned firstlongitudinal magnetic bias layers is demagnetized to the partiallydemagnetized first magnetic bias field strength of from about 25 toabout 50 percent of the first magnetic bias field strength.